Regulatory Mechanisms Underlying Postural Stability

姿势稳定性的调节机制

• 批准号: 6621452
• 负责人: Emily A Keshner
• 金额: $ 31.01万
• 依托单位: REHABILITATION INSTITUTE OF CHICAGO D/B/A SHIRLEY RYAN ABILITYLAB
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-04-01 至 2005-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6621452
• 关键词: biomechanics; cerebellar disorders; clinical research; environmental adaptation; human subject; labyrinth disorder; neuroregulation; posture; sensorimotor system; visual fields

The broad aim of this proposal is to examine how the CNS compensates for the loss of sensory and motor inputs during the production of postural reactions. In order to reveal the control signals involved in compensatory adaptation, response modulation over time must be examined. It is hypothesized that when sensory or motor function is impaired, postural behaviors become more constrained and response options decrease. Reduced control options may be sufficient in a constrained environment that requires a limited repertoire of response behaviors. In a complex environment with multiple signals, however, responses may not be adaptive to stimulus context. Specifically, adaptive modifications between the head, neck, and trunk during random and predictable linear translations in healthy subjects and in those with labyrinthine loss and cerebellar damage while seated in the dark with and without the trunk constrained will be examined. Response kinematics (head and trunk angular velocity and muscle activations) will be analyzed with overlapping windows of Fast Fourier Transforms to examine the time-frequency behavior. Center of pressure and center of mass will be calculated to estimate effective stiffness and damping characteristics of the adaptation process. The head will be weighted or the neck stiffened to investigate how an inertial field modifies the time- frequency behaviors. Statistical analyses will determine whether a damaged CNS exhibits the same rate of adaptation to these changes. We will quantify these control parameters using a recursive nonlinear system identification of incremental stiffness and damping matrices. Physiological control variables will be predicted using the homeomorphic computational model of the head and neck developed in this lab. Using a virtual environment, the contribution of dynamic visual inputs to the time varying adaptation process and the relative influence of a dynamic visual field on the head-neck-trunk responses will also be examined. It is hypothesized that patients with labyrinthine loss will select a single control strategy of increasing stiffness, thereby interfering with the coordinative process between the head and trunk. Patients with cerebellar lesions will be unable to modulate so that their responses are either excessive or suppressed. The functional consequences of labyrinthine loss and cerebellar control on postural orientation and stability are not well defined. Quantification of the adaptation process should reveal its effectiveness in a natural, dynamic environment and may suggest methods for remediation of postural instability.

该提案的广泛目的是检查中枢神经系统如何弥补姿势反应产生期间感觉和运动输入的损失。 为了揭示补偿性适应所涉及的控制信号，必须检查响应调节。 假设感觉到感觉或运动功能受损时，姿势行为变得更加限制，并且反应期权减少。 在受约束的环境中，减少的控制选项可能足够，这需要有限的响应行为库。 但是，在具有多个信号的复杂环境中，响应可能不会适应刺激环境。 具体而言，在健康受试者的随机和可预测的线性翻译以及迷宫损失和小脑损伤的患者中，头部，颈部和躯干之间的自适应修饰将被检查。将通过快速傅立叶变换的重叠窗口分析反应运动学（头部和躯干角速度和肌肉激活），以检查时间频率行为。压力中心和质量中心将计算以估计适应过程的有效刚度和阻尼特征。 头部将加权或颈部僵硬，以研究惯性场如何修饰时间频率行为。 统计分析将确定损坏的中枢神经系统是否表现出适应这些变化的速率。 我们将使用递归的非线性系统识别增量刚度和阻尼矩阵来量化这些控制参数。 生理控制变量将使用本实验室中开发的头部和颈部的同构计算模型预测。 使用虚拟环境，还将检查动态视觉输入对变化的适应过程的贡献以及动态视野对头颈螺旋响应的相对影响。 假设迷宫损失的患者将选择一种单一的控制策略来增加刚度，从而干扰头部和躯干之间的协调过程。 小脑病变的患者将无法调节，因此其反应过多或抑制。 迷路损失和小脑控制对姿势取向和稳定性的功能后果尚未很好地定义。 适应过程的量化应揭示其在自然，动态环境中的有效性，并可能提出修复姿势不稳定的方法。